Induction-coil controller.



M. P. MITCHELL.

INDUCTION COIL CONTROLLER.

APPLlCATlON FILED DEC.3I, 1915.

1,222,885. Patented Apr. 17,1917.

Witnesses lnventor I W b M y Y 1 I I Attorneys MARY PIERSON MITCHELL, 0F EATON, OHIO.

INDUCTION-COIL CONTROLLER.

Specification of Letters Patent.

Patented Apr. 17, 1917.

Application filed December 31, 1915. Serial No. 69,687.

To all whom it may concern:

lle it known that I, MAnYPmRsoN MITCH- TILL. a citizen of the United States, residing at Eaton, in the county of Preble and State of Ohio, have invented a new and useful Induction-Coil Controller, of which the following is a specification.

The present invention appertains to induction coils. and aims to provide novel and improved means wherein/"when the primary of the induction coil is overcharged, there will not be an overcharge in the current induced in the secondary.

It is also within the scope of the invention to provide a device of the nature indi cated which is comparatively simple and inexpensive in construction.

\Vith the foregoing and other objects in view which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed can be made within the scope of what is claimed without departing from the spirit of the invention.

The invention is illustrated in the accompanying drawing, wherein Figure 1 is a side elevation of one form of the invention.

Fig. 2 is another elevation, the line of view being at right angles to the line of view of Fig. 1, and portions being broken away and shown in section.

Fig. 3 is a diagrammatical view of a modification.

Referring to Figs. 1 and 2, the induction coil is designated generally by the numeral 1, and embodies the primary coil or winding 2 one terminal, designated 3, of which is adapted for connection with one conductor (not shown) of the alternating current generator or battery circuit. The other terminal, designated 4, of the primary coil 2 is connected to a governor of suitable kind, to the upper end of a relatively small electromagnet coil 5, and the lower end of said coil 5 has a terminal 6 adapted for connection with the other conductor of the generator or battery circuit. The magnet coil 5 may be parallel with and adjacent the upper end of the primary coil 2, and thesecondary 7 of the induction coil 1 is associated with the primary coil 2 in the ordinary manner.

The lower end of the induction coil 1 is secured upon a suitable base 8, and the core 9 of the induction coil has attached to its upper end a horizontal yoke 10 projecting over the coil 5. Attached to the yoke 10 is a depending governor core 11 projecting through the coil 5. A portion of the insulation of the coil 5 is cut away, at the lower end of said coil, and the exposed portion of the coil is soldered or otherwise electrically connected, as at 12, to the core 11.

A swinging armature switch 13 is pivotally engaged at one end upon a screw or pivot element 14 threadedly or otherwise engaging two convolutions of the primary coil between the terminals of said coil, so

that the armature switch 13 is electrically connected with the primary'coil between its terminals. The free end of the switch 13 cooperates with the lower end of the core 11, said core also serving as a contact for the engagement of theswitch 13.

The switch 13 is normally swung downwardly out of contact with the core 11 by means of a coiled contractile spring 15 connecting the switch 13 and base 8, although a weight or magnet may be used for the same purpose. The base 8 has a stop 16 for limiting the downward movement of the switch 13 to hold the free end thereof sufiiciently close to the core 11, so that when said core is magnetized, it will attract the armature switch 13.

The coil 5 is wound in the same direction as the primary coil 2, so that ordinarily, the magnetic flux which extends from the core 9 along the yoke 10 and into the core 11, will be opposed by the magnetic flux produced in the core 11 by the coil 5. Consequently, when a current of normal strength is impressed on the primary coil and magnet coil 5 which is in series therewith, the armature switch 13 will not be attracted by the core 11, but should there be an overcharge, the magnetic flux within the core 11 will be increased sufficiently by the increased enerlgization of the coil 5, to attract the armature switch 13 into contact with the core 11. This will shunt a portion of the primary coil 2 and the magnet coil 5, since the cur rent need only flow through a portion of the coil 2 between the terminal 3 and switch 13, and from said switch the current can flow by way of the core 11 and connection 12 immediately to the terminal 6 without flowing through the coil 5. As a result of a portion of the primary coil being shunted, the current induced in the secondary 7 is decreased accordingly, to prevent an overcharge in the secondary, and the magnetic flux created by the active portion of the primary coil will be sufficient to hold the switch 13 attracted to the core 11, until the current is again normal, in which event the spring 15 will withdraw the switch 13 from the core 11, to restore normal conditions. When the portion of the primary coil is shunted, this reduces the ampere turns of the primary and the lines of force in the magnetic field created by the primary, it being understood that the greater number of turns in the primary winding, the stronger will be the field created thereby. Therefore, when the portion of the primary winding is shunted, this will reduce the induction between the windlngs.

In the variation illustrated in Fig. 3, the induction coil 1 embodies an alternating current primary winding or coil 2 surrounding the upstanding core 9' carried by the base 8, the terminals 3 of the coil 2 being adapted for connection with the conductors of the generator or battery circuit. The secondary winding 7' is movable vertically upon the core 9 to and from the primary coil 2, and an electromagnet 5' has its terminals 4 connected to certain convolutions of the primary coil 2', to shunt a portion of the primary coil, the electromagnet 5 being normally deenergized due to the resistance offered thereby.

Disposed above the electromagnet 5 is a soft iron weight 13' forming an armature for the electromagnet, and cords or flexible elements 1'? connect the armature weight 13 and secondary Winding 7 and are passed over suitable pulleys or guides 18, whereby the weight 13 and secondary winding 7 normally balance one another, the secondary winding 7, however, being slightly heavier than the weight 13 in order that the secondary winding will gravitate onto the primary coil 2 when the electromagnet 5 is deenergized.

Ordinarily, the secondary winding 7 being disposed adjacent to the primary coil will have a maximum amount of current induced therein, but should the primary coil become overcharged, the electromagnet 5 will be energized by the excessive current, and will attract the armature weight 13, thus lowering said weight, and raising the secondary winding 7 away from the primary coil 2. Consequently, the current induced in the secondary winding will be reduced, to prevent an overcharge therein.

In the form illustrated in Figs. 1 and 2, the switch 13 can be placed in diiferent arrangements, so long as it is connected electrically with the induction or transformer coil. It is also possible to reverse the device, whereby when the E. M. F. decreases, the device is operable for increasing the current induced in the secondary to maintain the desired E. M. F.

IVit-h the form illustrated in Fig. 3, instead of the weighted armature 13' being used, a spring pressed armature can be employed.

Having thus described the invention, what is claimed as new is:

'1. In a device of the character described, an induction coil embodying primary and secondary windings, an electromagnet connected to the primary winding and adapted to be energized operatively by an overcharge, and means controlled by said electromagnet for changing the induction between said windings.

2. In a device of the character described, an induction coil having primary and secondary windings, and means operated when one winding is subjected to an overcharge for shunting a. portion of one winding.

3. In a device of the character described, an induction coil embodying primary and secondary windings, an electromagnet connected to one winding and means controlled by said electromagnet and operable when attracted whereby to shunt a portion of one winding.

4. In a device of the character described, an induction coil having primary and secondary windings and a core, a yoke connected to one end of said core, a secondary core carried by said yoke, a winding upon the secondary core and connected to one of said windings, and a pivoted armature switch having its free end adjacent to the secondary core to be attracted thereto, said armature switch being connected to one of the first mentioned windings and arranged to shunt a portion of said winding when attracted to the secondary core.

In testimony that I claim the foregoing as my own, I have hereto aflixed mysignature in the presence of two witnesses.

MARY PIERSON MITCHELL.

Witnesses:

HARRY L. RISINGER, JOHN Riemann. 

